Household pets among veterans with multiple sclerosis and age-matched controls. Pilot survey.

A pilot study was carried out among 22 Vietnam-era male US veterans with multiple sclerosis (MS) and 55 age- and sex-matched controls for prior exposure to dogs, cats, and animals with a distemperlike illness. No difference in dog ownership, or sick animals, and subsequent human illness was found in the group with MS or the control group. However, the distribution of dogs by indoor-outdoor status, as reported by patients with MS or controls, showed significant variation by tier of residence. Indoor dogs were more common in northern than southern latitudes, and this may be an important finding in light of the variation in the risk of MS with latitude.